The functional state of the intestine depends on the allocation of pancreatic and intestinal enzymes. The pancreatic enzymes are mainly involved in digestion, resulting hydrolyses to 20–50 % of macromolecular compounds to more simple nutrients that experience splitting during membrane digestion. Secretory the ability of the pancreas determines the intensity of the digestive processes and in other areas of the digestive tract and has a direct connection with the general metabolism of the whole organism of bird.

Many studies have proved the influence of different types of feed and BAR, as substrates, on the functional activity of intestines. So, methionine is an important source of sulfur, which is part mucositis, substances, preventing the digestion of the walls of the stomach and intestines with digestive enzymes. Lack of lysine in the diet affects the activity of digestive enzymes, especially of pancreatic enzymes, protein content of which varies from 0,1 to 10,0 %, and the vast majority (72 %) are proteolytic enzymes. When lack of lysine decrease in their activity birds are stunting. Threonine also plays an important role in the digestive system. High concentrations are found in the mucous membrane of the digestive tract, where this amino acid is involved in the synthesis of mucin, which protects from dehydration lower layers of the mucous membrane and the bowel wall from influence of microorganisms, and also promotes the synthesis of digestive enzymes.

During the research activity of enzymes in the tissues of the pancreas, it was established that during the experiment, it was greater in quails from the experimental group compared to control. In the pancreas quails, which was added to the diet amino acid complex, proteolytic enzyme activity on the 25th day of the studies had a tendency to increase, On the 40th and 55th day of the experiment was significantly more respectively 22,9 % and 18,4 %, than the birds of the control group.

The study amilaze activity of pancreatic tissue is found that in quail in the diets added lysine, methionine and threonine, it was also somewhat higher. In particular, the likely growth of the activity of amylase in the pancreas quail research group was observed on the 40th day by 25,9 % (p<0,01) and the 55th – by 18,4% (p<0,01). In our opinion, this fact can testify that the activity of the enzyme is increased by increasing its synthesis tissue of the pancreas.

In the pancreas quail research group lipolytic activity was significantly longer in the 40-th day by 7,9 % (p<0,05) and the 55th – by 12,1 % (p<0,01) compared to the control. This may indicate that the addition to the ration of amino acid complex impact on the biosynthesis and activity of lipolytic enzymes of the digestive system quail.

The definition of digestibility of feed nutrients, and the study of the nature of metabolic processes in the organism of a bird, is one of the important methods of evaluation of the use of various biologically active additives to the food. The degree of provision birds nutrients, in addition to having their necessary amount in the diet, as determined by the level of digestion and absorption into the body. Therefore, largely objective assessment of the value of amino acids in the processes of functioning of the digestive system can be given based on the study of the digestibility of nutrients in the body of quail.

The data analysis should be noted that the bird research group digestibility of most of the nutrients of the diet has improved compared with quails in the control group. Thus, the ratio digestibility of organic matter increased by 5,9 % (p<0,05) and protein 5,2 % (p<0,05). On the digestibility of fat, fiber there was only the tendency to improvement in the experimental group.

The results of physiological studies have found a positive effect of lysine, methionine and threonine on the activity of digestive enzymes by the pancreas. Established improve the digestibility of organic matter and protein, which will ensure the normal course of physiological processes and maximize performance of the quails.

Key words: quail, lysine, methionine, threonine, digestive enzymes, protease, amylase, lipase, digestion, absorption of nutrients.